Abstract

Centella asiatica (L), a herbaceous plant belonging to the family Apiaceae, possesses great medicinal value owing to the presence of important and characteristic triterpenoids as secondary metabolites. These triterpenoid secondary metabolites are found in leaves in substantial quantities whereas negligible amounts may be detected sometimes in root tissues. In the resent study direct rhizogenesis was induced from C. asiatica leaf explants using different concentrations and combinations of auxins (IBA/IAA/NAA) leading to the production of distinct root morphotypes. A number of culture conditions such as pH, nature of carbon sources (glucose, fructose, mannitol and maltose) as well as concentrations of sucrose exhibited their strong influence in terms of induction of root morphotypes, accumulation of total secondary metabolites and expression of key pathway genes. Phytochemical profiling using HPLC revealed that all root morphotypes accumulated enhanced amounts of triterpenoids. The enhanced phytochemical accumulation was further validated by the coherent pattern of expression of key genes related to their biosynthetic pathway in root morphotypes. The results have revealed that the hormonal combinations in the culture media not only mediated differential morphogenic responses but also regulated secondary metabolites accumulation in non-transgenic rhizogenic roots. The results of the study are promising for the utilization of such in vitro root morphotypes. The root morphotypes may act as alternative bioresources for the production of industrially important and leaf associated asiaticosides and other important triterpenoids for the commercial purposes.

Keywords

Asiaticoside Centella asiaticaGotu kola Madukparni Rhizogenesis

Jyoti Singh and Farzana Sabir have equally contributed to this work.

Electronic supplementary material

The online version of this article (doi:10.1007/s10725-014-9931-y) contains supplementary material, which is available to authorized users.

Notes

Acknowledgments

JS and FS are thankful to CSIR, New Delhi and UGC, New Delhi for financial assistance in the form of senior research fellowship. The authors wish to express their sincere thanks to the director, CSIR-CIMAP, for constant encouragement and providing necessary facilities. The financial Grant from DBT, New Delhi to carry out above studies is gratefully acknowledged.

Supplementary material

Supplementary material HPLC profiles of (a-b) with respect to the four major bioactive authentic compounds resolved under standard conditions; (c), representative HPLC chromatogram of extract from the C. asiatica roots produced by induction of rhizogenesis by media supplementation with auxins (1mgl−1) IBA (PPT 277 kb)